Basically, to excel as a group, you had to know each other's weapons well. Made warriors nice to have because they knew all weapon types and could tailor what they wield.

What happened, was that if you all used different weapons that each character had little or no grasp of your ability to fight was penalized. You would get in each other's way, you could even, absolute extreme cases, trip up one another or accidently hit a party member.

Warriors had a skill that allowed them to work better with spellcasters, with channellers, and psions. And the only way to improve upon it was to travel with them. Rogues had one that allowed them to work better with warriors.

If your group had large issue with weapon knowledges, the compensation was that you learned a lot about other weapon types, that you could, as you traveled together.

If you all had perfected the weapons wielded by all, you got some neat little progs that went off making your group do some cool combat stuff. :)

Nice idea you had, but it would have to be put in place carefully and hopefully have some unique style to it. ;)